Hello Freezybird49, is it timing you out? If so, it may be the resource pack, check out this post it should fix your issue depending on what it is: http://forums.pokefind.co/index.php?threads/resource-pack-solutions.3813/ also, make sure that you are on a Minecraft version 1.10+
What does it say when it crashes? Their should be a error message of some sort, also did you try all those options on that list?
If it has not been fixed yet, try allocating more RAM to Minecraft, a tutorial to do so will be here.